Brake system

ABSTRACT

A vehicle mounted boom for supporting working implements and having side swing movement is provided with a brake which is operative alternately with the boom swing motor to prevent the boom from swinging whenever it isn&#39;&#39;t being moved by the motor.

United States Patent Noller et al.

[ 51 Sept. 30, 1975 BRAKE SYSTEM' I Inventors: Fred W. Noller, Northville; James Leroy Campbell, Westland, both of Mich.

Assignee: Massey-Ferguson, lnc., Detroit.

Mich

Filed: Feb. 21, 1974 App]. No.'. 444,615

US. Cl 214/138; 188/170 Int. Cl. .l E02F 3/32 Field of Search 214/138, 132; 188/170 References Cited UNITED STATES PATENTS 6/1958 Pehkonen et a1. 214/138 R 1033,394 5/1962 Kashargen 214/138 R 3.136.399 6/1964 3,217,910 11/1965 3,762,777 10/1973 3 791 492 2/1974 3,830,336 8/1974 Reimbold, Jr. et a1. 188/170 Primary E.\'aminer-R0bert l Spar Assistant Examiner-Ross Weaver Attorney, Agent, or FirmThomas P. Lewandowski 5 7 ABSTRACT A vehicle mounted boom for supporting working implements and having side swing movement is provided with a brake which is operative alternately with the boom swing motor to prevent the boom from swinging whenever it isnt being moved by the motor.

3 Claims, 4 Drawing Figures US. Patent Sept. 30,1975 Sheet 1 of4 3,908,843

US. Patent Sept. 30,1975 Sheet 2 of4 3,908,843

US. Patent Sept. 30,1975 Sh eet3of4 3,908,843 I US. Patent Sept. 30,1975 Sheet 4 of4 3,908,843

BRAKE SYSTEM The use of side to side swingable booms for supporting working implements, such as buckets, shovels, crane hooks etc., with the boom mounted on a vehicle is well known, for example, on trenchers and backhoes. Industrial machines such as backhoes are comming into wider use today giving rise to a demand for greater versatility in the machines. One operation which is becoming increasingly popular with backhoes is that of using the boom for craning to set pieces in a trench, for example. Particularly, where the pieces being set constitute a heavy load it is important to have complete control over the swing of the boom to prevent override by the load which could capsize the machine.

In machines designed to handle a digging load, the override problem could be overcome by quickly reversing the direction of the controls for swinging the boom, but where the load is heavy a quick reversal would aggravate the problem because the reaction forces arising from a reversal of the large inertial force in the load would add to the forces tending to capsize the machine.

The above problems have been addressed by providing speed control and cushioning internal to the actuator for swinging the boom but the solution is a costly one and while adequate for handling the digging load generally cannot or are not, for practical reasons, designed to meet the burden of the heavy loads associated with a craning operation.

The present braking system overcomes the above problems by preventing override from occurring with a brake on the boom to prevent it from swinging whenever the boom is not being positively swung by the actuator. The system can result in the elimination of the need for speed control and cushioning under some circumstances and has the further advantage of stabilizing the position of the boom, for example, during the digging operation when trenching.

Another advantage of the system is its ability to automatically sense override and activate the brake.

The present invention relates to brake systems and more particularly to systems for side swingable booms mounted on vehicles which prevent side to side movement of the boom whenever the boom is not being positively positioned by the swing actuator. In one embodiment the system includes a base in the form of a mast frame mounted on a vehicle such as a backhoe with a swingable boom support mounted on the base. An actuator interconnects the base and support to provide for relative movement therebetween. Also included in the system is a means for stopping the above relative movement having as a part thereof a selective engaging member mounted on the base and an engageable member which is selectively engagable by the engaging member. The engaging member, for example a plate such as a brake disc or the like, is mounted on the boom support. The engaging member could be a brake caliper or similar type engaging means such asa friction clutch. Means for controlling the engaging member to permit selective engagement and disengagement of the engageable member are provided and can take the form of hydraulic controls where, for example, the actuator is a hydraulic cylinder. Included as part of the controls would be a control, such as a directional spool valve, for directing flow to the cylinder, an energy source, such as a driven pump and a remotely operated stopping means, such as a hydraulically operated disc brake whereby the cylinders and brake could be alternately operated to permit movement of the boom support when operating the cylinder and preventing movement when the cylinder is not being operated. Further, the controls can also include two additional valves such as check valve one each in conduits connecting to each of the directional flows from the directional spool valve, where it is bidirectional, and located between the bidirectional valve and the brake to prevent reverse flow through one conduit when the other conduit is receiving the directional flow from the control valve.

Referring to the drawings:

FIG. 1 is a fragmentary elevational view of a braking system mounted on a backhoe in accordance with the present invention;

FIG. 2 is an alternate embodiment of the braking system in FIG. 1 illustrating the use of a rotary cylinder therein;

FIG 3 is a schematic of controls for the system illustrated in FIG. 1; and

FIG. 4 is a schematic of controls for the system illustrated in FIG. 2.

Referring to FIG. 1 a base in the form of a mast frame 10 illustrated broken away from a vehicle such as a tractor or crawler (not illustrated) on which the mast frame 10 is mounted in a conventional manner. A yoke 12 is part of and mounted on the mast frame 10 and extends rearwardly of the vehicle. Connected to the yoke 12 is a swingable boom support in the form of casting 14 having bifurcated extensions 16 mating with the yoke 12 upon which it swings through a horizontal plane. The pivot of the boom support is formed by pins 18 aligned on a vertical axis and fixed in relation to casting 14 while being pivotal in the yoke 12. A boom 20 is pivotally mounted on the casting 14 for movement through a vertical plane. Actuation of the boom support is accomplished with a pair of hydraulic cylinders 22 (one illustrated) interconnecting the casting 14 with -the mast frame 10. The rod end of the cylinders 22 is connected by a pin 24 which may be pivoted with respect to the rod of the cylinders 22 or a bifurcated boss 26 on the casting 14. A similar pivotal connection (not illustrated) connects the cylinder 22 to the mast frame On the pivot is mounted a brake disc 28 preferably mounted on the pin 18. It is to be understood that the engageable member of the brake need not be a disc but could be a plate which is a segment ofa disc or any suitable plate attached to the boom support in a fixed manner. Further, the plate need not be located on the pivot, although this is the preferable location, but could be mounted eccentrically on the casting 14. The engageable member is complimentary to an engaging member in the form of a brake caliper 30 which is fixedly mounted on the yoke 12 in a position to receive a portion of the disc 28.

An example of a disc brake which is suitable for the brake system would be one manufactured by Tol-O- Matic'of Minneapolis, Minn. The brakes may be pneumatic or hydraulic and may include a fail safe feature whereby they are spring loaded to come on when the pressure on the brake falls. Further, the brakes can be operated on dual line systems or single lines depending on whether flow or pressure are used to actuate them. In the embodiment illustrated in FIG. 1 there is a single line 32 forming a conduit to connect the brake caliper 30 to the control means to be described below.

FIG. 2 illustrates an alternate embodiment to that of FIG. 1 wherein a rotary cylinder 34 which may be pneumatic or hydraulic replaces the linear cylinders 22 of FIG. 1. It is to be understood that the actuators and brakes illstrated may be other than fluidly operated, for example, an electrically controlled and operated system would be possible even though the hydraulic system illustrated is preferred for service on a backhoe.

It will be noted that when the rotary cylinder 34 is used the pivot is formed by the shaft 36 of the cylinder 34. The shaft 36 may be continuous at the bottom end of the cylinder 34 passing through the casting 14 and terminating in the yoke 12, or could terminate in the casting 14 with an additional pin connecting the bottom of the casting 14 to the yoke 12. In either case the shaft 36 is fixed relative to the casting 14 and pivotal with respect to the yoke 12.

The shaft 36 passes through the rotary cylinder 34 which operates to rotate it and on which is fixedly mounted the disc 28. The housing 38 of the rotary cylinder 34 is fixedly attached to the yoke 12 and in this embodiment becomes in effect a part of the base, mast frame 10, to permit the brake caliper 30 to be mounted on the housing 34 where it can engage the disc 28. In addition to the line 32 connected to the caliper 30 there are three other conduits illustrated in FIG. 2 as part of the controls together with a valve assembly 40 mounted on the housing 38. Line 42 is a supply, line 44 is a return and line 46 is a low pressure line connected to the return side of the fluid source.

FIG. 3 is a schematic of the apparatus illustrated in FIG. 1 together with the means for controlling it. As pointed out for the apparatus above, other control means could be used so as to be compatible with the apparatus being controlled even though the control means illustrated is hydraulic which is preferred for application on a backhoe. The control means include a bidirectional valve 48, check valves 50 and 52 and an unloading valve 54. The fluid source is a pump 56 having as complimentary equipment a reservoir 58 for returning flow and a relief valve 60 to protect the pump 56. The relief valve is located between a supply line 62 and return line 64 being within line 66. Both supply and return lines 62 and 64 are connected to the bidirectional valve 48 which is illustrated in a neutral position whereby flow is returned directly back to the pump 56. Shifting the valve 48 to the right causes a line 68 to become a supply line and line 70 a return line. Under the above conditions check valve 50 in a line 72 permits flow to line 32 connected to caliper 30 and to a line 74 in which the check valve 52 prevents flow to build up pressure on line 32. The pressure overcomes the spring bias on the caliper 30 to release the disc 28 in FIG. 1. At the same time, line 68 is pressurizing the cylinders 22 to swing the boom to the right in reference to the position of the cylinders 22 in FIG. 3. Shifting the valve 48 back to neutral lowers the pressure in the supply line 62 which is signaled to the unloading valve 54 via line 78 to permit the spring bias on the valve 54 to shift it to the position illustrated and dump the fluid from line 32 through line '76. Dumping the fluid in line 32 allows the caliper 30 to again engage the disc 28 and thereby maintain the position of the boom 20. Further, movement of the valve 48 to the left reverses the above described flow to the cylinders 22 to swing the boom to the left requiring check valves 50 and 52 to reverse their functions in order to release the caliper 30. It

should be noted that any tendency of the load to override the boom 20 and valve 48 will result in a drop in pressure in the supply line 62 which will be sensed by the signal line 78 to activate the caliper 30. Thus, the brake will come on whenever the load overrides the boom without a need to reverse the valve 48.

It would be possible to achieve the above results by using pressure to actuate the caliper 30 but such a system would not be operable upon loss of pressurized fluid.

FIG. 4 is a schematic of the apparatus illustrated in FIG. 2 together with the means for controlling it. The fluid source is the same as in FIG. 3 as is the bidirectional valve 48, supply line 62, return line 64 and line 32 connected to the caliper 30. Lines 68 and are replaced by the return and supply lines 42 and 44 for the rotary cylinder 34, and the valve assembly 40 is illustrated by the relief valves 80 and check valves 82 enclosed within the phantom line. The check valves 82 function in the manner described for those in FIG. 3 only in this case they permit flow to be reversed to the rotary cylinder 34 to prevent anti-cavitation. The relief valves 80 are to protect the rotary cylinder 34 in the manner described above for the relief valve 60 on the pump 56. A common low pressure line 46 connects the components of the valve assembly 40 back to the reservoir 58. I

The check valves 50 and 52 in FIG. 3 have been replaced by the grammatically illustrated check valve and orifice assemblies 84 and 86 located in lines 88 and 90. The functional combination of valve and orifice can sometimes be achieved with a properly sized orifice plate which permits free flow in one direction while restricting flow in the other direction. Thus, for example, when line 88 is permitting free flow across the check valve of assembly 84 the check of assembly 86 closes forcing all the flow through the orifice of assembly 86 causing a pressure differential sufficient to overcome the bias on the caliper 30 and release the brake on the boom 20. Reversing the flow with valve 48 reverses the function of assemblies 84 and 86 to obtain the same results of releasing the brake caliper 30. With the valve 48 in the neutral position illustrated in FIG. 4 there is no flow in lines 88 and 90 and therefore no pressure differential to overcome the bias on the caliper 30'resulting in the activation of the brake.

Should an override condition occur when the brake is released a pressure drop will occur in either line 88 or 90 as the load forces the boom to move ahead of the pump 56 thereby causing actuation of the caliper 30 to stop further movement of the boom 20.

Where a pressurized system is used a single assembly like assemblies 84 and 86 would permit a lag time on the activation of the brake to overcome a jerky stop.

The assemblies 84 and 86 of FIG. 4 are interchangeable with the checks 50 and 52 plus unloading valve 54 of FIG. 3 and vice versa.

The above braking systems are operative to brake the boom 20 whenever the valve 48 is not actuating the cylinders 22 or 34, and in addition to brake the boom 20 whenever an override condition occurs without requiring any further action on the part of the one operating the valve 48.

In accordance with the provisions of the patent statutes the principle and mode of operation of the control have been explained and what is considered to represent its best embodiment has been illustrated and deable member selectively engageable by the engaging member and mounted on the support, means for controlling said engaging member comprising: a directional valve for directing flow to said actuator, an energy source, and conduits interconnecting all the above for directing flow to said actuator to swing the boom, 21 second valve and an orifice, a conduit, containing said second valve and orifice, interconnecting said directional valve with said stopping means, said second valve preventing flow from said stopping means and said orifice restricting return flow to create a pressure differential to prevent sudden actuation of said stopping means when said directional valve is operated and to activate said stopping means when said directional valve is not in operation.

2. The brake system defined in claim 1 wherein said directional valve is bidirectional for directing flow to said actuator in two directions enabling the boom to swing to either side of the vehicle, and including biasing means for maintaining said stopping means normally engaged, including: a third valve and second orifice; conduits, one pair of a valve and orifice in each, connecting each of the directional flows of said bidirectional valve with said stopping means to restrict reverse flow through one conduit when said other conduit is receiving the directional flow from said bidirectional valve to create a pressure differential sufficient to overcome said biasing means to release said stopping means when operating said actuator and to apply said stopping means when said actuator is not being operated.

3. The brake system defined in claim 2 wherein said first and second pairs of a valve and an orifice are replaced by an orifice plate capable of permitting free flow in one direction and metered flow in the opposite direction. 

1. In a vehicle having a boom swingable to the side of the vehicle for supporting working implements, a brake system including a base mounted on the vehicle, a swingable boom support mounted on the base, an actuator interconnecting the base and the support for providing relative movement therebetween, means for stopping the relative movement including a selective engaging member mounted on the base and an engageable member selectively engageable by the engaging member and mounted on the support, means for controlling said engaging member comprising: a directional valve for directing flow to said actuator, an energy source, and conduits interconnecting all the above for directing flow to said actuator to swing the boom, a second valve and an orifice, a conduit, containing said second valve and orifice, interconnecting said directional valve with said stopping means, said second valve preventing flow from said stopping means and said orifice restricting return flow to create a pressure difFerential to prevent sudden actuation of said stopping means when said directional valve is operated and to activate said stopping means when said directional valve is not in operation.
 2. The brake system defined in claim 1 wherein said directional valve is bidirectional for directing flow to said actuator in two directions enabling the boom to swing to either side of the vehicle, and including biasing means for maintaining said stopping means normally engaged, including: a third valve and second orifice; conduits, one pair of a valve and orifice in each, connecting each of the directional flows of said bidirectional valve with said stopping means to restrict reverse flow through one conduit when said other conduit is receiving the directional flow from said bidirectional valve to create a pressure differential sufficient to overcome said biasing means to release said stopping means when operating said actuator and to apply said stopping means when said actuator is not being operated.
 3. The brake system defined in claim 2 wherein said first and second pairs of a valve and an orifice are replaced by an orifice plate capable of permitting free flow in one direction and metered flow in the opposite direction. 